Overall, IE dropped to a 63.6% share, a new all-time low, as it lost just over 1 percentage point of market share. November marked the third straight month Microsoft's browser has declined by a point or more; in the last year, IE has fallen 8 percentage points.

The only bright spot for Microsoft is that it's made some headway in an unsubtle campaign to convince users to abandon the eight-year-old IE6 for this year's edition, IE8. When Net Applications accounts for IE8's "compatibility view" -- a feature that lets users display sites as rendered by the older, and often Web standard-incompatible IE7 and IE6 -- Microsoft's newest browser accounted for 22.1% of all browsers, a virtual dead heat with IE6 and several points above IE7's 16.9%.

Microsoft has been aggressively promoting IE8 for several months, most famously last August when Amy Bazdukas, the general manager for IE, said "Friends don't let friends use IE6."
Yesterday, Microsoft continued that campaign as it touted IE8 as a safer browser than the earlier editions for holiday online shopping. "We've said it before and we'll say it again, to advance the Web we need to move people to a modern version of Internet Explorer," said Ryan Servatius, a senior product manager in the IE group, during an interview Monday.

But even with calls to action like those, Microsoft has had trouble retaining the users who have ditched IE6 and IE7. By Net Applications' tally, IE6 has lost 3.2 percentage points in the last three months, and IE7 has fallen 4.2 points; IE8, however, has gained only 4.2 percentage points in the same period.

The seemingly inexorable slide in IE's share has left the door open for rivals, including Firefox, Chrome and Opera.

Last month, Firefox added about 0.7 of a percentage point to its share, finishing November with 24.7%. Chrome grew by 0.4 of a percentage point and Opera increased by 0.1 of a percentage point, to end the month at 3.9% and 2.3%, respectively. All three browsers' shares were records.

Most notable were the gains by Firefox and Chrome. Firefox neared the 25% milestone, which it should pass this month, and Google's browser closed in on Apple's Safari, which lost market share for the first time since last April. If the trend from the past three months continues, Chrome will pass Safari and take the No. 3 browser spot in January 2010.

Chrome's growth is impressive, in part because it's been fueled almost exclusively by the Windows version, the only edition that has made it out of developer and beta testing. Google plans to issue a beta of the Mac version this month, which could add even more to its momentum going into the new year.

Opera also gained ground on Safari last month, and now accounts for more than half the market share controlled by Apple's browser.

Mozilla has enjoyed additional success in migrating its users to Firefox 3.5, the upgrade launched last June, although its uptake pace continued to slow. In November, Firefox 3.5 increased its share by another 1.3 percentage points to 15.2%, in line with October's 1.25-point increase but dramatically less than the 3.8-point surge of September. Firefox 3.0 slipped 0.7 of a percentage point to end at 8.1%.

Firefox 3.0 users face the retirement of their browser in January 2010, when Mozilla will stop serving up security updates for the 18-month-old application. Before then, Mozilla should have wrapped up Firefox 3.6, a minor upgrade that Mozilla said last week is still on track for a 2009 ship date.

IE, however, remains the browser to watch, if only to track its decline, which Microsoft has not managed to stem with the March 2009 release of IE8. Since then, IE has lost 4.8 percentage points, almost as much as the 5.8 points it fell in the same eight months of 2008.

Projecting IE's slide using Net Applications' data, Computerworld estimates that IE will slip under the 50% share mark in December 2010 if the loss trend of the last three months holds.

Net Applications measures browser usage by tracking the machines that visit the 40,000 sites it monitors for clients, which results in a pool of about 160 million unique visitors per month.